Faceting Design Diagram: Precede – Tourmaline, Achroite, Dravite, Rubellite, Indicolite, Verdelite, Siberite


Tourmaline (Achroite, Dravite, Rubellite, Indicolite, Verdelite, Siberite)

Precede Jeff Graham Facet Design

Precede Jeff Graham Facet Design

Precede (MIR83.JRG)

By Jeff R. Graham
Copyright 2005
91.2% Light Return
Angles for R.I. = 1.62
32 facets + 12 facets on girdle = 44
4-fold, mirror-image symmetry
96 index
L/W = 1.000 P/W = 0.450 C/W = 0.191
H/W = (P+C)/W+0.02 = 0.661 P/H = 0.681 C/H = 0.289
Vol./W^3 = 0.239

 

Addition # 10 – Cut in refractive indexes 1.62 to 2.14 with no changes. This is very interesting and not difficult to cut. It works well in light to medium saturations and is a good Garnet cut. Note: P3 just floats in, you can vary the facets. A table should be cut on larger stones.

Precede Jeff Graham Facet Design

Detailed faceting instructions by Jeff Graham available at The Rock Peddler